I just found a mongoose on the side of the road this morning in the trash. Naturally, I grabbed it. I've got an 85 Mongoose M1 so I know a little about serial numbers. I know that I've got a 1979 Mongoose made in the month of June. Aside from that though. i haven't a clue. I was wondering if anyone would know what the original specs on this bike are. Currently it has gold plated components....wheels, ACS hubs, Toughneck stem, Dia Compe MX brakes. I would love to know if this was the factory setup.

For 79 bike shop owners were already making different builds for the "showroom floor". As well as people building part by part for thier own personal touch. Here is one pretty much standard, the bars could be wider but being 79 and mid year, could be narrow or wide. I am sure some "experts" will chime in with a lot more details.
1979 Blue Mongoose

or

1978 Nickel Mongoose

Unless there is a "T" in the serial number before or after the rest, it's just a Mongoose. It would have came with either Motomags or Araya 7C's and an Ashtabula stem, but the items you have on it could have been added at the point of purchase when new. The Araya's would have had Shimano hubs.

My bad - the Motomag could have came with heavy duty steel wheels also. Here's a couple pic's from the catalog:

sweet. Any chance you have a hi-res version of those catalog pics? I'd love to be able to read the copy.

Based on those photos, if I had to venture a guess as to the model I'd say it was a Mongoose II. Also...this is the style of gooseneck I have on the bike.

forgot to upload the photo first time